Kirby's brakes

[John Larson <jdlarson@ix.netcom.com>]

Kirby, brake squeaks when freely turning are likely to be caused by a
couple of factors, which are related. Aside from wheel bearing play,
sticking calipers, both from piston problems and from saddle problems,
are most likely. Slightly out of true rotors can also contribute to the
problem. Here's where it gets fun. A dragging caliper can cause the
rotor to warp due to the heat build up from the constant friction. The
rotor and the pads can glaze from the heat, requiring you to use the
brakes harder for a given situation-more heat, more problems. The heat
built up at this point doesn't dissipate because the pads are dragging,
the glaze on both the pads and rotors gets worse........
You'll need to service the calipers, true the rotors (some out of round
is necessary to push the pads back), deglaze or replace the pads,
possibly even replace the hoses (always a good idea every few years in a
bad climate) and, as always, flush the coolant. If you have ABS, this
last step is of extreme importance, and you will have to do both front
and rear brakes at the same time to maintain the integrity of the
system.
After all the years I've spent in the business, I still have a hard time
with brake noises, and I think that brake noise complaints are among the
most common in the German car repair business. BMW keeps changing the OE
pads and rotors, and has a ton of tech tips on stopping the noise, and
they still don't have it right. I always ask the counterman for the
current recommended pad/rotor combination when doing a brake job on a
Bimmer (In this instance, the dealer prices are competitive with the
aftermarket.) I know Porsche, Mercedes Benz, and I'm sure VAG have the
same problems. On BMW and MBZ, rotors are considered a service item, and
are cheap enough to replace rather than surface. Good luck in your quest
for the answers to life, the universe, and all that stuff.
John.